Ensure that the session id is sanitized before issuing
the scan request. During the transient stages of a new
interface when no session exists for that interface and
if a scan is received for that particular interface, it
would result in scan with invalid vdev id. Validate the
session id to avoid the same.
Change-Id: Ib22262493a141491d1d86ae682b14113d303685d
CRs-Fixed: 973773